NTN Uplink Synchronization Timer for Closed-Loop Offset Adjustment
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Solution Overview
Problem
The challenge in non-terrestrial networks (NTN) is determining uplink synchronization or out-of-synchronization after introducing closed-loop frequency domain offset adjustment, particularly for IoT devices that cannot perform GNSS measurements in the RRC connected state.
Innovation Solution
A communication method involving a terminal device running a timer upon receiving a message for frequency domain offset and/or timing advance adjustment, and determining uplink synchronization based on the timer's state, with network devices sending adjustment commands to manage the timer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed-loop frequency domain offset adjustment is introduced in NTN system, then frequency offset correction capability is improved, but uplink synchronization determination becomes unclear
Solution Approach 1:
The patent implements a feedback mechanism where the network device monitors uplink signal reception status and sends timing advance adjustment commands to the terminal device based on detected timing offsets. This closed-loop feedback enables continuous synchronization maintenance without requiring complex GNSS measurements, resolving the contradiction between improving frequency offset correction and simplifying synchronization determination.
2Measurement precision
If GNSS measurements are required for uplink synchronization, then synchronization accuracy is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent enables the terminal device to maintain uplink synchronization through network-device-provided timing advance commands rather than self-performed GNSS measurements. The network device performs the measurement function centrally and distributes adjustment commands to terminals, allowing IoT devices to achieve synchronization without complex measurement capabilities, thus resolving the contradiction between synchronization accuracy and device complexity.
3Ease of operation
If timer-based synchronization management is implemented, then uplink synchronization maintenance is simplified, but synchronization response time increases
Solution Approach 1:
The patent implements a dynamic timer management mechanism where the timer duration and restart conditions are adaptively controlled based on uplink signal reception status. The network device can dynamically adjust timer parameters and send adjustment commands to restart or extend timers, balancing the simplicity of timer-based management with responsive synchronization updates, thus resolving the contradiction between ease of operation and response time.
Data Source
AI summary
Provided are a communication method and a communication apparatus. The method comprises: after receiving a first message sent by a network device, a terminal device runs a timer, wherein the first message is used for the terminal device to perform frequency domain offset adjustment and/or timing advance (TA) adjustment; and the terminal device determines, according to the running state of the timer, whether uplink out-of-synchronization has occurred.